Imaging systems of various designs have been used extensively for generating images. Exemplary imaging systems include copiers, scanners, cameras, and more recently digital cameras, and other devices capable of generating images. Color imaging systems have also experienced significant improvements and are increasing in popularity. Color imaging systems may be calibrated to increase accuracy of various image processing algorithms (e.g., illuminant estimation, color correction, etc.), and also to increase the color accuracy of final reproductions.
For example, even identically configured imaging systems may vary from one another due to product tolerances or design variances. Referring to FIG. 1, a graphical representation of relative responsivity versus wavelength is shown for two hundred digital cameras corresponding to the same product. FIG. 1 illustrates the variations in blue, green, and red sensor responsivities of the sampled cameras represented by respective bands 4, 6 and 8. The illustrated bands have widths illustrating the size of the variations between respective cameras although the cameras structurally comprise the same components.
One color calibration technique uses reflective charts. Reflective charts can be utilized to calibrate a camera quickly and they are relatively inexpensive. However, calibrations implemented using reflective charts may not be accurate enough for utilization with cameras. Monochromators, on the other hand, can produce very accurate calibrations of color imaging systems including cameras. However, the calibration procedure with monochromators may take a relatively long period of time to complete, the devices are expensive, and an accurate and controlled light source is typically used.
Other conventional arrangements for analyzing imaging devices have associated drawbacks. For example, one device for shutter testing of an imaging device (e.g., a Camlogix SH-T2) utilizes incandescent lamps and a time calibrated sensor placed in a film plane of a film camera which is less practical for testing of digital cameras. Further, usage of incandescent lamps presents issues with respect to controlling the duration of illumination as well as color and luminance of emitted light. Scanners have been calibrated using white cards which does not permit color calibration in color implementations. Other devices for testing lenses and color (e.g., K-Series TV Optoliner available from Davidson Electronics) utilize a test pattern which is projected onto a sensor plane. These systems have drawbacks of careful set-up and being designed for analyzing television cameras. In addition, typical conventional analysis systems use different pieces of equipment for performing different tests or analysis.
At least some aspects of the disclosure are related to improved imaging device analysis devices, systems and methods.